Caulking has been used in the building trades for both utilitarian and aesthetic reasons to cover open spaces, gaps or cracks between or within various structural members. Caulking or glazing compounds are often used between metal panels, over expansion joints, around perimeters of door frames and window frames, between adjacent concrete slabs, and between a concrete slab and a foundation.
The use of caulking material as a sealant around a window, sink, bath tub or shower stall and its adjacent structural elements such as a wall or floor has been known for some time. Such caulking materials are used to prevent infiltration of water and water borne salts into cracks and to provide a more aesthetic appearance. Without a proper seal, water generally seeps into the crack, typically under the influence of capillary action, penetrates into the underlying structure such as plaster, sheet rock, thus, rotting, mildewing or molding the wood, and staining adjacent surfaces such as the wall or ceiling below. This necessitates expensive repairs.
Caulking materials for the purpose of this application include putty, glazing materials and caulking materials. The composition of caulking materials varies considerably. An example of caulking material is a silicone rubber disclosed in U.S. Pat. No. 3,639,155 (Hartlein et al.). Generally, caulking materials have a rubbery base which is plasticized, filled and tackified to provide a deformable plastic mass which generally has immediate adhesion for the surfaces upon which it is applied. The rubbery base caulking materials usually comprise a substantial portion of rubber such as butyl, polysulfide, polychloroprene, room temperature vulcanizable silicone or acrylic rubber. Such rubbery materials may be in latex form. The caulking materials are typically compounded to a putty-like consistency with fillers such as calcium carbonate, zinc oxide, silica, tackifiers such as polybutene oils or terpene resins, plasticizers such as polybutene oils, thixotropes such as clays or colloidal silicas and antioxidants. Other typical compounding ingredients may also be included. Some caulks will cure to a non-tacky state while others retain their applied physical properties. The curing time for certain curable caulking materials to achieve a tack-free surface is often long, causing accumulation of dust particles on its surface, which can result in an unsightly appearance.
However, it is often desirable to remove the caulking materials from the substrates to which they have been applied. Caulking materials can be removed in a number of different ways. For example, they can be physically removed by chipping or scraping. However,these methods have been less than satisfactory. Because of the caulking material's tendency to strongly adhere to a substrate, prying or scraping the material from the substrate can cause undesired damage to the underlying substrate. To overcome this problem, U.S. Pat. No. 4,582,540 (Allback) discloses that the caulking material can be heated prior to being physically removed. A drawback associated with heating is that the substrate can crack or even burn.
As an alternative to the laborious and often less than satisfactory outcome resulting from the physical removal of caulking materials, chemical solvents have been used. One drawback associated with chemical solvents is that they have a tendency to flow off the caulk thereby making repeated applications necessary. In addition, many solvent compositions are undesirable because they are too volatile and thus, readily evaporate once applied to the caulking. Other compositions are highly flammable thereby posing application, handling and shipping problems. In addition, to posing application and handling problems, some of these solvents are undesirable because of their adverse effects upon the atmosphere and their toxicity.
Another drawback associated with the solvent compositions is that they generally dissolve only caulks made of polymeric material of a polarity similar to the solvent according to the rule "like dissolves like." Thus, caulks made of non-polar material will dissolve in non-polar solvents and caulks made of polar polymeric material will dissolve in polar solvents, but not vice versa. Therefore, many of these solvent compositions have been deficient because they cannot dissolve caulks made of materials of different polarity.
U.S. Pat. No. 4,956,115 (Van De Mark) discloses the use of a paint stripper used to remove a wide variety of coatings including silicon elastomers. The Van De Mark paint stripper comprises an oil-in-water emulsion whose discontinuous phase includes 1,3,5-trioxane, an aliphatic alcohol, an aliphatic ester and an aromatic compound.
U.S. Pat. No. 4,927,556 (Pokorny) also discloses a water-based composition utilized to remove coatings such as paints and varnishes which eliminates many of the adverse effects of solvent-based systems. The Pokorny Patent does not teach nor does it suggest that its composition, which consists essentially of at least one dibasic ester, water and one thickening agent, may be used to remove caulking.
Thus, there currently exists a need for a caulking remover which dissolves caulks made of polymeric materials of different polarities and which is fast and effective and yet, does not exhibit many of the adverse effects associated with solvent-based compositions.